Most of my characters don't have ref sheets; when I'm commissioning art, I just send a couple of drawings to provide some approximation of what the character looks like, and a swatch for the artist to eyedrop colors from. Sometimes an artist will deviate from that approximation, or add their own little flourishes or fill in the blanks on missing details, and then I'll wind up adding it to the handful of examples I send to the next artist. So a lot of my characters go through this unintentional, group-activity iterative design process.
As an example, my jackal character, Jackal, started as a stream-sketch commission by @floe. While I was feeling the character out, I sent that drawing to @wasabitea_ and asked them to draw a plantigrade version of the same character. Later on, I sent just the plantigrade drawing to @_pocketss and asked them to draw a digitigrade version. That resulted in the character's design as it is presently.
